Background: Hypoxia inducible factor-1 alpha (HIF-1α) plays a critical role in tumoral angiogenesis and HIF-1α overexpression is associated with an increased risk of patient mortality in many cancers. A number of studies have introduced perfusion computed tomography (CT) as a monitoring modality for antiangiogenic therapy.
Purpose: To investigate significance of volumetric perfusion CT parameters in relationship to HIF-1α expression in VX2 tumor rabbit models.
Material and methods: Twenty VX2 carcinoma tumors of bilateral back muscles of 10 rabbits were evaluated with serial volumetric perfusion CT in 7, 10, and 14 days after tumor implantation. CT perfusion data were analyzed to calculate blood flow (BF), blood volume (BV), and permeability surface area product (PS) of whole tumor and non-necrotic peripheral area (periphery). Immunohistochemical analysis of HIF-1α expression and microvessel density (MVD) was performed.
Results: HIF-1α was expressed in 12 tumors; two, three, and seven tumors classified as scores 1, 2 and 3, respectively. Mean MVD was 24.85 ± 13.7. PS of both the whole tumor and periphery showed positive correlations with HIF-1α score (r = 0.41, P = 0.046; r = 0.43, P = 0.002, respectively). BV of periphery showed a negative correlation with HIF-1α (r = -0.48, P = 0.040). There was strong positive correlation between HIF-1α expression and MVD (r = 0.82, P < 0.001).
Conclusion: In VX2 tumors, volumetric perfusion CT parameters were of limited value for the prediction of HIF-1α activity although HIF-1α expression was found to be weakly positively correlated with PS and negatively correlated with BV.
Keywords: Hypoxia inducible factor-1 alpha (HIF-1α); angiogenesis; microvessel density; perfusion computed tomography (CT).
© The Foundation Acta Radiologica 2015.